ABSTRACT All patients are at risk for unplanned hypothermia in the perioperative practice setting. Adverse outcomes attributed to hypothermia include myocardial events, surgical site infections, poor wound healing, increased blood loss, and prolonged postanesthesia care unit stays. The AORN “Guideline for prevention of hypothermia” includes recommendations for measuring the patient's body temperature, selecting methods for prevention of unplanned hypothermia, and implementing the selected insulation and warming interventions. This article discusses guideline recommendations related to using a consistent temperature measurement method through all phases of perioperative care, assessing risk for hypothermia in all patients, and prewarming perioperative patients. A scenario provides an example in which an interdisciplinary facility team uses a gap analysis and a risk assessment to determine the process for implementing recommendations from this guideline. Perioperative RN s should review the entire guideline for additional information and for guidance when creating and updating policies and procedures related to unplanned hypothermia.